Galileo Mission to Europa

Galileo has been orbiting Jupiter since late 1995, and completed its 29th orbit in
December 2000. Galileo travels around Jupiter in elongated ovals ---
each orbit lasts about two months. By traveling at different distances from Jupiter,
Galileo can sample different parts of the planet's extensive magnetosphere. The orbits are
designed for close-up flybys of Jupiter's largest moons.

RTG = radioisotope thermoelectric
generator

On December 16, 1997, the Galileo spacecraft flew within 200 km of
Europa's surface,
allowing its cameras to resolve details as small as 6 meters.